Active Ingredients and Antioxidative and Anti-EV71 Virus Effects of Grifola frondosa Ethanol Extract

  Objective  Active ingredients and antioxidative and anti-EV71 virus activities of the Grifola frondose extracts using varied concentration of ethanol were analyzed.

  Method   Using 55%, 70%, and 95% ethanol solutions, a ultrasound-assisted extraction was conducted to produce concoctions from G.frondosa fruiting bodies.Content of active ingredients and efficacy of the extracts obtained with varied concentrations of ethanol as an antioxidant and anti-EV71 virus agent were determined.

  Result  The content of polyphenols at 0.042% and that of triterpenes at 1.82% were the highest in the 95% ethanol extract (GFE95) of all concoctions.The maximal polysaccharides at 33.08% and proteins at 17.45% were found in GFE55 that used 55% ethanol for the extraction.GFE95 also showed the greatest antioxidant capacity with IC₅₀ on scavenging DPPH, ABTS⁺, O₂⁻, and H₂O₂ free radicals of 0.742 7 mg·mL⁻¹, 0.741 4 mg·mL⁻¹, 0.902 6 mg·mL⁻¹, and 0.414 6 mg·mL⁻¹, respectively, and a strong antiviral effect on EV71 at the concentration of 200 μg·mL⁻¹ with the inhibition rate of 88.18%, an IC₅₀ of 194.80 μg·mL⁻¹, and a TI of 9.65.A Pearson’s correlation analysis indicated that the DPPH, ABTS⁺, and O₂⁻ free radical scavenging rates significantly correlated to the triterpenoids content with correlation coefficients of 0.992, 0.971, and 0.613, respectively (P＜0.01); the O₂⁻ and H₂O₂ free radical scavenging rates significantly correlated to the polyphenols with correlation coefficients of 0.921 and 0.997, respectively (P＜0.01); the anti-EV71 virus effect significantly correlated to the polyphenols and triterpenoids with correlation coefficients of 0.536 and 0.954, respectively (P＜0.01); and the triterpenoids and polyphenols significantly correlated to the antioxidative and antiviral activities of the extract.

  Conclusion   The 95% ethanol extraction of G.frondosa optimally retrieved the active substances, such as polyphenols, triterpenes, and polysaccharides, in the fruiting bodies.The extract exhibited significant antioxidative and antiviral capacities, with which a valuable pharmaceutical material might be developed.